Lubricating oils used in internal combustion engines contain dispersants to maintain engine cleanliness. Typical of such dispersants are the succinimides described in U.S. Pat. No. 3,178,892 and the Mannich condensation products of U.S. Pat. Nos. 3,413,347 and 3,697,574. High molecular weight polyolefins containing polar groups have more recently been described which have both dispersant and viscosity lift properties. Typical of these are those described in U.S. Pat. Nos. 3,316,177; 3,326,804; 3,445,387; 3,388,067; 3,404,091; 3,404,092; 3,513,095; 3,687,849; 3,687,905; 3,756,954; 3,842,010; 3,872,019; 3,923,930; 4,002,569 and 4,032,700.